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Phys Ex Final
Terms in this set (50)
A response to a stimulus that is not under conscious control
The sense of the body's position in space and of the position of body parts relative to one another is called
In a reflex arc or loop what is the function of the afferent neuron?
To carry information from the receptor to the spinal cord.
The intramuscular receptor that detects the rate and degree of muscle stretch is known as
What does the Golgi tendon organ detect?
Muscle force or tension
Define the term agonist.
The agonist is the muscle which acts as the prime mover in a given movement.
Free nerve endings are nociceptors. What do these receptors detect?
What do the Ruffini corpuscles detect?
Stretch in the skin
Which type of muscle fiber has the highest aerobic energy capacity?
Which type of muscle fibers produce the most force?
Type II (or Type IIb/x)
Define motor unit.
An alpha motor neuron and all the muscle fibers it innervates
Define rate coding.
Increasing or decreasing the force output by altering the firing frequency of motor units.
Altering force output by activating more motor units is known
Define the size principle.
The size principle states that smaller, type I motor units will be recruited first and as force requirements increase larger type II units will be recruited.
Give one example of a situation in which the size principle does not apply.
Explosive or maximal efforts such as vertical jump or heavy lifting or electrical stimulation.
Stimulation of a muscle fiber or motor unit at frequencies too high to allow any relaxation causes what type of contraction?
What are the three phases of a muscle twitch following the application of an electrical stimulus?
Lag phase, contraction phase, and relaxation phase
In what type of contraction is there force production and muscle fiber shortening?
Define isometric contraction in terms of muscle fiber length.
It involves force production with no change in length.
What is the difference between an isotonic and isokinetic action?
In an isotonic action the load is held constant but the speed of contraction can vary, but in an isokinetic action the speed is held constant but the force output can vary.
The relationship between the length of the muscle fiber prior to contraction and its maximal force production capacity is called the
In the length-tension relationship why does force production capacity reach 0 on the right side of the graph?
Because the muscle fiber is so stretched that actin and myosin cannot form any cross-bridges.
In the length-tension relationship what is passive tension and when does it increase?
Passive tension is the elastic recoil of the stretched tissue and it increases as the fiber is stretched beyond optimal length.
In the length-tension relationship the point at which the greatest amount of cross-bridges can be formed is called
On the force-velocity curve describe the relationship between force and velocity during concentric contraction.
As velocity increases force decreases.
On the force-velocity curve a velocity of 0 describes what type of contraction
On the force-velocity curve, power is maximized at what % of maximal force?
Pre-stretch of the agonist muscle(s) prior to maximal contraction in order to increase force production is known as the
What are the four components of the stretch-shortening cycle?
Parallel Elastic Component (connective tissue around muscle), Series Elastic Component (Tendinous Attachments), Contractile Component (Contractile Proteins in Muscle), and the Stretch Reflex
The phase of plyometric exercise that describes the transition period between eccentric and concentric phases is known as the
Describe an example of a plyometric movement and identify its components.
Phases are resting, eccentric, amortization, and concentric
The inability to maintain a given workload is known as
Fatigue caused by reduced outflow of motor impulses from the brain and spinal cord is known as
Muscle soreness that begins after exercise and typically reaches a peak in 24-48 hours is known as
delayed onset muscle soreness (DOMS)
What two factors in exercise are most closely associated with DOMS?
Exercise novelty and eccentric contractions.
What is the cause of DOMS?
Inflammatory response caused by tissue damage from exercise.
The ability to produce force.
Increase in the cross-sectional area of muscle due to the increase in muscle fiber size is called
What adaptations are most responsible for increases in strength during the early phase of training?
When more motor units can be recruited simultaneously to produce force it is known as
What happens to muscle fiber types with training?
Type II fibers tend to shift from the type IIx towards type IIa, in other words, they become more fatigue-resistant. No change from type I into type II or vice versa.
In what two instances described in class can type II fibers turn into type I fibers?
Loss of type I motor units with age or nerve damage. Type II motor units can re-innervate the loose fibers and convert them.
What is the principle of reversability?
It states that if you cease training you will lose the fitness improvements.
The loss of fitness improvements following the cessation of training.
On average, strength can be maintained for about how long once training is stopped?
Re-stimulating a motor unit before it has completely relaxed will result in an increased force output. This phenomenon is known as
Which type of muscle fiber has the greatest fatigue resistance?
What is the function of the gamma motor neuron?
It causes contraction of the muscle spindle in order to set the sensitivity of the receptor.
What do Pacinian corpuscles detect?
They detect movement or pressure around joints
Define concentric contraction?
Force production with muscle fiber shortening.
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